According to the state of the art, electron-beam gun systems for picture recording and picture displaying installations are designed so that the electrons emitted by a hot cathode to form an electron-beam, pass a series of electrodes before they strike the impact surface (e.g. the inside of a television picture tube). The hot cathodes, which are conventionally used for this purpose, have peak beam current densities of about 0.5 A/cm.sup.2, for example for television picture tubes.
In addition to these hot cathodes, so-called high-current cathodes are known, such as are used to produce microwaves and have beam current densities up to 10 A/cm.sup.2.
It is further known that increased beam current densities from cathode arrangements, for example in picture tube electron-beam gun systems, produce improved, that is sharper images. As shown in this connection by electronic-optic research performed by the applicant, when the above indicated cathodes, which in this application are called high-current cathodes, are to be used in television picture tubes, it is necessary to keep the distance between the emitting surface of the high-current cathode and the grid 1-electrode, as well as the passing area of the electrodes through the grid 1-electrode, small, if the grid 2-voltage is to be maintained in the range of 800 to 1000 Volts. Tests to maintain the indicated conditions, performed in this regard by the applicant, were not successful in the past, because high-current cathodes require operating temperatures of 1100.degree. C. and such temperatures do not allow the grid 1-electrode to remain stable, because of its small width.
For that reason the invention had the task of presenting an electron-beam gun system which permits the use of high-current cathodes in picture displaying and picture recording installations. Since these high-current cathode-equipped beam gun systems are of particular interest for large-size picture tubes, and until now these tubes were only manufactured in small quantities, the invention had the further task of presenting a manufacturing process for electron-beam gun systems with high-current cathodes, which allows most of these beam systems to be used, without extensive conversion of the production lines that are used to manufacture electron-beam gun systems with conventional output hot cathodes.